Natural Rubber Mixtures With Low-Volatility Aging Stabilizer
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Solution Overview
Problem
Existing aging stabilizers for natural rubber vulcanizates have high volatility, which affects their processing and stability against ozone and oxygen, leading to issues like embrittlement and cracking.
Innovation Solution
The use of N,N′-dicyclohexyl-p-phenylenediamine as an alternative aging stabilizer, which reduces volatility and enhances the performance properties of rubber vulcanizates by improving tensile strength, elongation at break, and full vulcanization speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known phenolic, aminic, sulfur-containing or phosphorus-containing aging stabilizers are used, then oxygen, ozone, heat and storage stability of rubber vulcanizates is improved, but volatility in the vulcanization process is high
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of the aging stabilizer - specifically using N,N'-dicyclohexyl-p-phenylenediamine with cyclohexyl groups instead of smaller alkyl groups. This structural parameter change reduces volatility while maintaining the stabilizing function against oxygen and ozone, directly resolving the contradiction between reliability and substance loss.
2Loss of substance
If N,N'-dicyclohexyl-p-phenylenediamine is used as aging stabilizer, then volatility is reduced and mechanical properties are improved, but the spectrum of action against aging may be limited
Solution Approach 1:
The patent merges multiple functions into the single compound N,N'-dicyclohexyl-p-phenylenediamine. It simultaneously provides aging stabilization against oxygen and ozone, improves mechanical properties (tensile strength, elongation at break), and reduces volatility. This multi-functionality resolves the contradiction between specialized performance and broad adaptability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
N,N′-dicyclohexyl-p-phenylenediamine effectively stabilizes natural rubber vulcanizates against aging, reducing volatility and improving mechanical properties while maintaining low emission during production.
Implementation Method 1
natural rubber and synthetic diene rubbers contain double bonds. Specifically the reactive sites thereof in allyl position promote reaction with oxidizing agents such as ozone or oxygen. In the course of what is called aging, for example by contact with oxygen, the whole volume of the rubber article is oxidized
Implementation Method 2
A disadvantage of these known aging stabilizers is the high volatility thereof in the vulcanization of the rubber mixtures
Data Source
AI summary
New rubber mixtures on the basis of natural rubber and N, N-dicyclohexyl-p-phenylenediamine are extremely well suited for the production of vulcanized rubbers and moulded parts obtainable therefrom, in particular tires, tire parts or technical rubber articles with improved use properties.